Radical alternating copolymerization of vinyl ethers

New alternating equimolar copolymers of electrophilic trisubstituted ethylenes, methyl 3-phenyl-2-cyanopropenoate and 2-phenyl-1,1-dicyanoethene, with ethyl, n-butyl, i-butyl, t-butyl, 2-chloroethyl, and phenyl vinyl ethers were prepared by free radical initiation. Chemical compositions of the copolymers are 1 : 1 in broad ranges of monomer ratios. The copolymerization rate of both electrophilic monomers with the vinyl ethers increase in the series 2-chloroethyl > ethyl > phenyl > n-butyl > i-butyl > t-butyl. These variations in the reactivity of the vinyl ethers are discussed in terms of their preferred conformations in donor-acceptor complexes with electrophilic trisubstituted ethylenes. © 1993 John Wiley & Sons, Inc.     

Synthesis and Structure of the Centered Cluster Compound Ba3(Zr6Cl18Be)

Reaction of powdered Zr with ZrCl₄, BaCl₂ and Be in suitable proportions in a Ta container at 800°C produces the title compound. Suitable monocrystals for X-ray diffraction were obtained from reactions to which a comparable amount of Hg₂Cl₂ had been added. The structure of Ba₃Zr₆Cl₁₈Be is a superstructure of the K₂ZrCl₆ · Zr₆Cl₁₈H type (R3 c, Z = 6; a = 9.6852 (9) Å, c = 52.52 (1) Å; R, R_w = 2.7, 3.2% for 826 independent reflections, 2θ ≤ 50°). Trigonally compressed [Zr₆(Be)Cl₁₂ⁱ]Cl₆^a clusters are interconnected by six-coordinate barium atoms that lie in Cl^a antiprisms (a twisted version of the Zr^IV site) while (9 + 3)-coordinate barium substitutes for potassium within chlorine layers. Distortions associated with the size and field of barium are responsible for the superstructure and for differences from other analogues.     

Sorption of alkali metals and silver nitrates from binary and multicomponent solutions by a crown-containing polymer

The equilibrium in the systems containing a polymer based on dibenzo-18-crown-6 and binary or multicomponent aqueous solutions of NaNO₃, KNO₃, RbNO₃, and AgNO₃ was studied. The constants of the sorption of the individual electrolytes from solution into the polymer were determined. Preliminary calculations of the phase composition on sorption of 11 mixtures of electrolytes with a common anion from the data on the equilibria in the systems with one electrolyte are possible.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 464–466, March, 1993.     

Reexamination of the thermolytic rearrangement of 4-halophenyl azides to 2-aminophenols and other products

Summary The halogenation of derivatives of 2-aminophenol with N-chloro- and N-bromosuccinimides at ambient temperatures in acetic acid was studied. With the necessary compounds available, a reexamination of the thermolytic rearrangement of 2-halophenyl azides to 2-aminophenols and other products was undertaken. It is certain that the rearrangement of 4-halophenyl azides to 2-aminophenols occurs but the products identified in this study differ significantly from those reported previously by Suschitzky et al. (1963, 1966).

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Neuuntersuchung der thermolytischen Umlagerung von 4-Halogenphenylaziden zu 2-Aminophenolen und anderen Produkten

Zusammenfassung Es wurde die Halogenierung von 2-Aminophenol-Derivaten mit N-Chlor- und N-Bromsuccinimid bei Raumtemperatur in Essigsäure untersucht. Mit den zur Verfügung stehenden Verbindungen konnte eine Neuuntersuchung der thermolytischen Umlagerung von 4-Halogenphenylaziden zu 2-Aminophenolen und anderen Produkten unternommen werden. Diese Umlagerung findet sicherlich statt, allerdings differieren die dabei beobachteten Produkte signifikant von denen, die Suschitzky et al. 1963 und 1966 beschrieben.

     

Immobilization of poly(ethylene oxide) on polyethylene using a plasma-induced graft copolymerization process

A radio-frequency glow discharge induced graft copolymerization process has prepared a PAAc-grafted PE film in this present study. Poly(ethylene oxide) (PEO) was then covalently immobilized onto PAAc-grafted PE film by a chemical coupling reaction. Carboxylic groups were introduced onto the surface of PE film by exposing the film to an Ar plasma, and the plasma-treated film was then next reacted with a 50% acrylic acid aqueous solution. These functional groups were reacted with bisamino PEO by a coupling agent CMC. ESCA, IR, and water contact angle studies were conducted for characterizing the surfaces of these films during the varied stages of the reaction. Increasing the molecular weight of the PEO attached to the PAAc-grafted PE resulted in an increased wettability of the films. © 1993 John Wiley & Sons, Inc.     

抑制动力学荧光法测定草酸

在高氯酸溶液中,草酸对铁（Ⅲ）催化过氧化氢氧化罗丹明6G具有抑制作用,据此建立了高灵敏抑制动力学荧光法测定草酸含量的新方法。方法的线性范围为0．1～1．2mg/L;检出限为93μg/L。将方法用于人体尿液和菠菜中草酸含量分析,结果满意。     

非线性Af—Bg型自由基交替共聚反应的固化理论

利用高分子反应统计理论,给出了非线性Ａｆ－Ｂｇ型自由基交替共聚反应的溶胶－凝胶分配方程和反应体系的凝凝胶化条件,这些结果是进一步研究与凝胶网络性能相关的网络结构参数的基础。     

寡糖—8—氨基芘—1,3,6—三磺酸衍生物的毛细管电泳—激光诱？…

利用自组装的毛细管电泳－激光诱导荧光装置,研究了多种寡糖－８－氨基芘－１,３,６－三磺酸（寡糖ＡＰＴＳ）衍生物的分离。考察了电泳介质、浓度及pＨ对寡糖－ＡＰＴＳ 衍生物分离的影响,在酸性和碱性条件下,分别实现了痕量寡糖标准品及葡聚糖水解产物的高效分离。     

Structure of 6-Epiforsticine and Revision of the Stereochemistry of Forsticine

In the course of our investigation on Aconitum and Delphinium species, we have isolated a number of norditerpenoid and diterpenoid alkaloids from A. kuzsnezoffii and A. hemsleyanum var. pengzhouense1~6. We have found that a norditerpenoid alkaloid, 6-epiforsticine isolated from both plants shows a great deal of similarity to forsticine7 but significantly differed from the latter in its 13C NMR spectrum (Table l), suggesting that the alkaloids were a pair of epimers at C-6. The present comm…     

Synthesis and structure of a novel molybdenum imido calix[6]arene

Treatment of p-tert-butylcalix[6]areneH₆ (H₆L) with [Mo(OBu^t)₂{[2,2′-(N)-C₆H₄]₂(CH₂CH₂)}] in refluxing toluene affords, after work-up, the complex [Mo(2-NC₆H₄CH₂CH₂C₆H₄NHC(Me)NH-2^/)LH₂]·4MeCN (1), which contains an 11-membered metallocyclic ring as characterised by Synchrotron X-radiation.